Electrostatic and entropic interactions between parallel interfaces separated by a glassy film

Karen Johnston, M.W. Finnis

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

A simple classical density functional model is set up to describe the electrostatic and entropic interactions between two parallel planar charged interfaces separated by a thin film of a phase (the glass) containing a distribution of charged ions. The total charge in the system is zero. Three cases are treated: (1) the two interfaces carry a fixed surface charge; (2) the first interface carries a fixed surface charge, simulating a ceramic, while the second is held at zero potential, simulating a metal; and (3) both interfaces are held at zero potential. A discretized form of the nonlinear Poisson-Boltzmann equation is derived and solved by a Newton-Raphson method. The continuum approximation is compared with a model in which the ions are only allowed to occupy discrete planes. The effect of correlation among the ions is included within the local density approximation. Inserting parameters appropriate to the copper-alumina interface, we find that the attractive image force between the ceramic and metal dominates the entropic (DLVO) repulsive force in the 1-2 nm range.
LanguageEnglish
Pages2562-2568
Number of pages7
JournalJournal of the American Ceramic Society
Volume85
Issue number10
DOIs
Publication statusPublished - 1 Oct 2002

Fingerprint

Electrostatics
Ions
Surface charge
Metals
Local density approximation
Boltzmann equation
Aluminum Oxide
ceramics
Newton-Raphson method
ion
Copper
Alumina
metal
Glass
Thin films
aluminum oxide
glass
copper

Keywords

  • ceramic materials
  • approximation theory
  • alumina
  • electrostatics
  • entropy
  • interfaces (materials)
  • nonlinear equations
  • poisson equation

Cite this

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Electrostatic and entropic interactions between parallel interfaces separated by a glassy film. / Johnston, Karen; Finnis, M.W.

In: Journal of the American Ceramic Society, Vol. 85, No. 10, 01.10.2002, p. 2562-2568.

Research output: Contribution to journalArticle

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AU - Finnis, M.W.

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KW - approximation theory

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